chapter 5 unit ii: organization integumentary system part ii

Chapter 5

Unit II: OrganizationIntegumentary System

Part II

Five types of Exocrine glands:

1. Merocrine sweat glands

2. Apocrine sweat glands

3. Sebaceous glands

4. Ceruminous glands

5. Mammary glands

Skin OrgansCutaneous Glands


Sweat Glands (sudoriferous glands)

• Plasma and waste products– 500 ml of insensible perspiration/day– diaphoresis – visible sweating (1L/hr)

• Merocrine glands is a simple tubular gland – millions of them help cool the body

• Apocrine glands produce sweat containing fatty acids– found only near hair follicles after puberty– Scent glands that respond to stress and sex

Sebaceous glandLumen(hair removed)Wall of hair follicle

Basal lamina

Discharge ofsebumLumen

Breakdown ofcell membranesMitosis andgrowthGerminativecells


Sebaceous Glands

• Flask-shaped gland – opens into hair follicle– Some onto skin surface (pimples)

• Oily secretion called sebum– contains broken-down cells, fat, wax– lanolin in skin creams is sheep sebum


Ceruminous Glands

• Found only in external ear canal

• Produce cerumen

• Functions of earwax:

– waterproof

– keeps eardrum flexible

– bitterness repel mites and other pests


Mammary Glands

• Developed glands found only during lactation and pregnancy– modified apocrine sweat gland– Produce milk (lactate)– All individuals have undeveloped glands

– Must have high levels of estrogen to develop

• Mammary ridges or milk lines– 2 rows of mammary glands

• Polythelia – additional nipples– may develop along milk line

• Melanin = yellow, brown, and black hues– All individuals have same number of cells– Cells stimulated by UV radiation to become more active

• Hemoglobin = red• Carotene = yellow, orange from diet

– concentrates in stratum corneum and hypodermis

Skin Color(Pigmentation)

• Cyanosis = blueness from deficiency of oxygen in the circulating blood (cold weather)

• Erythema = redness due to dilated cutaneous vessels (anger, sunburn, embarrassment)

• Jaundice = yellowing of skin and whites of the eyes due to excess bilirubin in blood (liver malfunction)

Skin ColorAbnormalities

Skin ColorAbnormalities

• Pallor = pale color from lack of blood flow, dermal collagen shows thru (low blood pressure, emotional stress)

• Albinism = a genetic lack of melanin

• Hematoma = a bruise (visible clotted blood)

• Friction ridges– formed during fetal development– Unique pattern even for identical twins

• Flexion lines– Formed where skin folds during flexion of joint

• Freckles and moles =– Aggregation of melanocytes– freckles are flat; moles are elevated

• Hemangiomas– discolored skin caused by benign tumors of dermal blood

capillaries

Skin Markings

• Regeneration– replacement of damaged cells with original cells– Restores original function– Epidermis and liver

• Fibrosis– replacement of damaged cells with scar tissue (collagen)

• Function is not restored• healing muscle injuries, scarring of lung tissue in TB or

healing of severe cuts and burns of the skin (dermis)

Tissue Repair

Initial Injury

Immediately after theinjury, mast cells inthe region trigger aninflammatoryresponse.

Bleedingoccurs at thesite of injury.

Epidermis

Dermis

Wound Healing

Plasma carries:•Antibodies•Clotting factors•WBCs

Wound HealingAfter Several Hours

Blood clot forms to decrease blood lossand spread of microbes

Macrophages patrol thedamaged area

Cells of the stratumbasale undergo rapiddivisions to replace missing cells

After One Week

Fibroblasts

Wound Healing

• New capillaries grow into wound

• Fibroblasts deposit new collagen to replace old material

• Fibroblastic phase begins in 3-4 days and lasts up to 2 weeks

After Several Weeks

Scartissue

Wound Healing

• Epithelial cells multiply and spread beneath scab

• Scab falls off

• Epithelium thickens

• Connective tissue forms only scar tissue (fibrosis)

• Remodeling phase may last 2 years

• Production of tissues and organs in the lab

– Build a scaffold - polyester or collagen fibers

– seeded with human cells

– grown in “bioreactor” to supply O2 and nutrients

• Skin grafts already available

– research in progress on heart valves, coronary arteries, bone, liver, tendons

Tissue Engineering

• Hot water, sunlight, radiation, electric shock or acids and bases

• Leading cause of accidental deaths from: • fluid loss – loose up to 75% of plasma within a few hours• infection

• Treatment – nutrition and fluid replacement, debridement and infection control

Skin DisordersBurns

Skin DisordersBurns

(b) Second degree (c) Third degree(a) First degree

• Tumors “swelling”– abnormal growth, cells multiply faster than they die

• Benign = not cancer– slow growth, connective tissue capsule, stays local

• Malignant tumor = cancer– 3 properties:

– fast growing – unencapsulated – metastatic

– stimulate angiogenesis

Cancer

• Carcinogens – environmental cancer-causing agent

– chemical = cigarette tar, food preservatives, industrial chemicals

– Radiation = gamma and UV

• Bone density scan = 1 day of natural radiation

• X-rays = 10 days

• CT scans = varies (head = 8 months; abdomin/spine = 3 yrs)

– Viruses = type 2 herpes simplex - uterus, hepatitis C - liver

Causes of Cancer

Carcinogens

• Mutagens = Carcinogens – trigger gene mutations

• Defenses against mutagens and tumors

− Scavenger cells – remove mutagens

− Peroxisomes – neutralizes free radicals

− Nuclear enzymes – detect & repair damaged DNA

− Natural killer cells – immune surveillance

− Macrophages and monocytes secrete tumor necrosis factor

Two types of genes responsible:

• Oncogenes – tells a cell to grow

– sis oncogene causes excessive production of growth factors

– ras oncogene codes for abnormal growth factor receptors

– ¼ of human cancers

• Tumor suppressor genes (TS)

– Tells a cell to stop growing

– damage to both removes control of cell division

– ½ the cases of Leukemia, colon, lung, breast, liver, brain

• Requires 5-10 mutations at different loci

• Death results from metastasis not the original tumor

Malignant Tumors

• 90% of malignancies are carcinomas

• High rate of mitosis

• More exposed to carcinogens

• All skin cancers are malignant!

• Induced by UV rays of the sun

– basal cell carcinoma

• arises from stratum basale and invades dermis

• Most common

• Easiest to treat

Skin DisordersSkin Cancer


– squamous cell carcinoma

• arises in stratum spinosum

• metastasis to the lymph nodes can be lethal


– malignant melanoma

• Commonly arises from melanocytes of a preexisting mole

• Least common

• Most deadly

• ABCDE--asymmetry, border irregular, color mixed and diameter over 6 mm, evolving

• UVA and UVB are improperly called “tanning rays” and “burning rays”

• As sale of sunscreens has risen so has skin cancer

– Does not protect against skin cancer, just sunburns!

– Higher incidence of basal cell carcinoma because people falsely assume they can stay out longer

– Some chemicals in sunscreen may damage DNA and generate harmful free radicals when exposed to UV rays

• Sunblock is better because it scatters and reflects UV rays

• Learn more at http://www.ewg.org/2013sunscreen/

Skin DisordersUVA, UVB

Chapters: 3, 4, 5 Spelling matters!

• Fill in the blank 3x5 notecard

• Multiple Choice

• Matching

• Short answer

• True/False

Exam 1

chapter 5 unit ii: organization integumentary system part ii

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